Auto exposure mode works extremely well in many situations and in fact for quick grab shots it may be your best bet. But if you want more control to be more creative, spend some time experimenting with Program, Aperture Priority and Manual modes. I promise that you won't regret it!
And, don't forget to read your camera's manual, read it again, and take it with you when you shoot. (After all, my "real" job, is as a technical writer.)
For more information, I highly recommend Bryan Peterson’s “Understanding Exposure”.